About 20 kilometers northwest of Amarillo, Texas, beneath a geological structure called the Bush Dome, lies the world’s largest repository of a substance that, sooner or later, will become more precious than gold: helium. Though best known as the lifting gas in balloons (and for the high squeaky voices it evokes when inhaled), helium’s buoyancy, inertness, and other unique properties make it irreplaceable for some of our civilization’s highest technologies. Without large amounts of helium, liquid-fueled rockets cannot be safely tested and launched, semiconductors and optical fibers cannot be easily manufactured, and cryogenically cooled particle accelerators and medical MRI machines cannot function. Helium may also prove crucial as a working fluid or even a fuel in future nuclear reactors. And unlike gold, which can be eternally recovered and shaped to new functions, only very expensive countermeasures can prevent helium, once used, from escaping into the atmosphere and drifting away into outer space.

Helium’s rarity on Earth and relative abundance in America are cosmic and planetary accidents. After hydrogen, helium is the second most common element in the universe, with the bulk of it formed during the big bang. This primordial material suffuses space, occasionally condensing to form dust, stars, and eventually planets. The Sun is rich in helium, as are the solar system’s gas giant planets. Earth likely once had a wealth of helium too, but this was boiled off by sunlight eons ago. Our modern supply of helium has gradually built up over billions of years in subterranean pockets of natural gas as a byproduct of decaying radioactive elements.

The same tectonic processes that led to the formation of the Rocky Mountains and of North America’s ancient inland sea also created one of the largest and most helium-rich natural gas pockets on the planet, beneath the Great Plains. It was discovered in 1903, when a Kansas oil field jetted a helium-spiked gas plume that wouldn’t burn. Only providence placed the helium in the geographic center of a rapidly industrializing nation that had just gained a capacity to efficiently extract it. The United States has provided the majority of the world’s supply ever since. For more than a century, helium has been as American as apple pie.

Helium’s “Fort Knox” is the Federal Helium Reserve (FHR) near Amarillo, created in 1925 to supply a fleet of military dirigibles that never fully materialized. During the Cold War, when helium was crucial for military and civilian space programs, the FHR linked up to a larger network of gas fields, pipelines, and refineries, growing to contain roughly a billion cubic meters of helium and accruing a $1.4 billion debt in the process. Though the FHR still holds more helium than any other stockpile by far, its stores are rapidly diminishing. Since 2003, the US Bureau of Land Management has been methodically selling off the FHR’s hoard (and repaying the $1.4 billion debt) in compliance with a 1996 Congressional act that called for phasing out the reserve by 2015.

Echoing years of complaints from the scientific community, in January the US National Research Council (NRC) released a report condemning the liquidation of the FHR as a shortsighted blunder that has thrown the global market into turmoil and hindered scientific research. The flood of federal helium, initially priced substantially higher than other sources, perversely contributed to helium’s commercial price increasing to meet and then exceed the FHR’s fixed price point. Consequently, the report says many university science laboratories (and, yes, purveyors of festive balloons) have seen their expenditures on helium more than double since 2006, and work-stifling shortages are common. Purchasing helium may now account for half of total operating costs at some US labs, leaving little left over for researcher salaries and other expenses. The report suggests that changing the price point of federal helium and allowing small-scale science labs to make collective purchases from the FHR could mitigate these effects.

Another contributor to helium’s rising price is a soaring global demand. Emerging powers such as China and India are ramping up helium-hungry activities like chipset fabrication, space programs, and cryogenic research. The failure to foresee this flattening of global commerce speaks volumes about the carefree buoyancy of America in the 1990s, when it was the planet’s sole superpower and stockpiling helium seemed more wasteful than squandering it. Now, the NRC report warns, if the US does not soon cease selling off its reserves, within 10 to 15 years the country will be forced to import most of its helium from the only other near-term sources, gas fields in the Middle East and Russia.

Beyond such mundane geopolitical rivalries, the US has a more profound reason to conserve its helium: Every balloon inevitably deflates. Optimistically assuming that demand for the substance continues to grow only a few percent each year, and that the entirety of the globe’s remaining natural gas reserves will be processed for their helium, the NRC report estimates there will only be enough to last another 40 years. It stands to reason that as supplies diminish, helium will be used more efficiently and investments in recycling technologies will grow. But the fact that the Earth’s four-billion year bounty has been so reduced in scarcely a century suggests that helium is sadly not long for this world.